I think the original Twilight Zone, and the original Outer Limits were superb shows, and I regularly seek out reruns. Another, not really sci-fi, but a great program was Night Gallery that Rod Serling did in the late sixties.
Another vote for "Night Gallery". I guess I'm an old show geek. I love the old classics. Night Gallery, Twilight Zone, Outer Limits, Night Stalker, and Andy Griffith. Also, M*A*S*H. Even though the last two are not a sci-fi shows.
I vote for Farscape there was something about Zhaan and Chiana that had my attention. Especially Zhaan, I guess it was the blue skin. You have to love those Delvians.
The Outer Limits was great! Also Voyage to the Bottom of the Sea around that same timeframe. Wild Wild West was good in a Jules Verne/Steampunk sort of way.
Another one I liked as a kid was Fireball XL5. They were ahead of their time in both story lines and technical aspects for a Saturday kids program. I got the DVD collection for XL5. Sting Ray was pretty good too.